Generator negative sequence protection method considering machine end unbalanced negative sequence current suppression characteristic

A technology with negative sequence current and suppression characteristics, which is applied in the direction of measuring current/voltage, photovoltaic power generation, emergency protection circuit devices, etc., can solve problems such as intrusion into generators, burns of generator rotors, and withdrawal from operation, so as to achieve safety, stability and protection Calculation, module clear effect

Pending Publication Date: 2022-08-09
CHINA THREE GORGES UNIV
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Problems solved by technology

[0006] In order to solve the problem that the negative sequence current invades the generator in the large-scale power transmission scenario, causing the generator rotor to be burned or even out of operation

Method used

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  • Generator negative sequence protection method considering machine end unbalanced negative sequence current suppression characteristic
  • Generator negative sequence protection method considering machine end unbalanced negative sequence current suppression characteristic
  • Generator negative sequence protection method considering machine end unbalanced negative sequence current suppression characteristic

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Embodiment Construction

[0071] A generator negative-sequence protection method considering the unbalanced negative-sequence current suppression characteristics of the generator, according to the change of the invading generator negative-sequence current and taking into account the heat accumulation effect, an inverse-time correction method for the generator's negative-sequence current based on the virtual A value is proposed. Make the protection action time more accurate with the change of the negative sequence current; under the system unbalanced condition, the negative sequence current of the machine terminal is compensated based on the chain STATCOM, the inverse time limit action time is predicted, and the minimum adjustment time of the unbalanced system notified by the stable system T s In comparison, two schemes of complete compensation and incomplete compensation are determined, and in the case of incomplete compensation, measures are taken to inform the operator to control or trip the three-pha...

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Abstract

The invention relates to a generator negative-sequence protection method considering a generator-end unbalanced negative-sequence current suppression characteristic. The method comprises the following steps: step 1, connecting an STATCOM compensation device in parallel to a generator-end system; 2, monitoring negative-sequence current at the end when the generator runs in real time; 3, correcting the inverse time limit A value of the generator, and predicting protection action time; and 4, considering the minimum adjustment time Ts of the unbalanced system, and determining complete compensation and incomplete compensation of the negative-sequence current of the machine end. The method comprises the following steps: designing STATCOM negative sequence output control on the basis of real-time monitoring of negative sequence current of a machine end, and calculating limit action time according to inverse time limit; and a complete and incomplete compensation strategy is provided, so that the negative-sequence current invading the generator can be eliminated or effectively reduced, and time is bought for safety and stability of a safety and stability control system.

Description

technical field [0001] The invention relates to the technical field of generator negative sequence current protection, in particular to a generator negative sequence protection method that considers the restraint characteristic of unbalanced negative sequence current at the generator end. Background technique [0002] With the wide application of new energy in the power system, more and more power networks have unbalanced problems, resulting in a large amount of negative sequence current. Although some high-voltage transmission lines use adaptive reclosing, there are always fault identification and reclosing delays. In the process of asymmetrical operation, the system generates a large amount of negative sequence current. The intrusion of negative sequence current into the generator not only damages the unit itself, but also may cause the generator in the stable control stage to be disconnected from the grid in severe cases, affecting the safety and stability of the system. ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02H7/06G01R19/165
CPCH02H7/06G01R19/165Y02E40/10Y02E10/56
Inventor 李振兴朱益胡聪贾倩薇谢志豪李振华翁汉琍黄景光
Owner CHINA THREE GORGES UNIV
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